Publications Archive

We investigate the phylogenetic affinites of the New Zealand blue duck (Hymenolaimus malacorhynchos), a riverine specialist of uncertain relationships, using 2613 bp of DNA sequence data from 3 mitochondrial genes. Hymenolaimus has variously been considered an aberrant Anas species, or an ancient taxa in the tribe Anatini. Presently, it is placed in a highly-derived clade (Tribe Merganettini) with the shelducks. Our findings show that Hymenolaimus forms a monophyletic clade, and does not fit within any of the other duck tribes around the world. Our study also confirms convergent evolution among duck species that inhabit fast flowing rivers.

Ruru or moreporks (Ninox novaeseelandiae) are an iconic native species that are relatively widespread in New Zealand, yet little is known about populations that reside within urban areas. Here we present results from a ruru survey conducted by volunteers within the city of Hamilton, New Zealand to: 1) collect baseline data for future comparative ruru surveys, and 2) to introduce and promote ornithology to a wider audience. In addition, these data may be used to quantify the success of urban restoration projects and pest control operations, as many of the desired outcomes of those projects (e.g., increased native vegetation and reduced mammalian predators) would have a positive impact on ruru numbers. Twenty sites were surveyed in areas such as amenity parks and gullys with established vegetation. Teams of observers recorded the time and approximate bearing of all ruru vocalisations at sites for 1 h each night for 5 consecutive nights between 2000-2230 hours in late October 2011. Ruru were detected at 80% (16/20) of sites at least once over the survey period; at 13 of these sites ruru were detected on >2 nights, while birds were detected every night at 5 sites. Multiple birds were detected at 11 sites, which suggested that some may have been resident pairs and breeding. We recommend that including members of the public in similar surveys is highly desirable as it raises awareness around conservation issues and introduces ornithology to a wider audience.

We report a polymorphic population of collared petrels (Pterodroma brevipes) apparently breeding on Vanua Lava, northern Vanuatu, in the austral autumn-winter. This is one of only 5 known extant colonies of the species. One of the 2 birds captured by us matched the description of the recently described dark plumaged Pt. b. magnificens which had never been reported caught ashore previously. However, the other bird caught was a paler individual indicating that the taxon is variable in plumage colour, like other Pt. brevipes populations. We suggest that the 2 other criteria used to define the subspecies Pt. b. magnificens (body size and breeding chronology) are also questionable and require further investigation.

We report on the discovery, care, release, and post-release monitoring of the 2nd vagrant emperor penguin (Aptenodytes forsteri) recorded from New Zealand. An immature male emperor penguin came ashore at Peka Peka Beach (40° 50’ S) 56 km north-east of Wellington on 20 Jun 2011. Its condition deteriorated over the following 4 days, and it was taken into care at Wellington Zoo on 24 Jun. Following 72 days of rehabilitation, the bird was released at sea at 51° 42’ S, 78 km north of subantarctic Campbell I, on 4 Sep 2011. He was tracked, via satellite transmitter, moving south-east for 113 km until 9 Sep, after which no further signals were received. The arrival, care and release of this penguin attracted unprecedented levels of public and media interest for a vagrant bird to New Zealand.

Deliberate taxon substitution is a much discussed but rarely enactioned concept in restoration ecology. We describe the successful establishment of a translocated population of Snares Island snipe (Coenocorypha huegeli) on Putauhinu I, which lies alongside Taukihepa (Big South Cape I), the last stronghold of the extinct South Island snipe (C. iredalei). Thirty Snares Island snipe were captured on North East I, Snares Is in Apr 2005 and released 3-5 days later on Putauhinu I. A survey on Putauhinu I in Mar 2011 resulted in the capture of 54 descendants of the released birds and a population estimate of at least 320 birds. This is one of few documented translocations of an organism with the specific objective of replacing a closely related extinct taxon. As a result, the Snares Island snipe is probably more abundant than at any time in its evolutionary history.

To date there has been no published information describing the relative abundance, behaviour or distribution of the New Zealand king shag (Leucocarbo carunculatus) within mussel farm areas, despite the sensitivity of the species to human disturbance and the potential overlap of its range with proposed development of marine aquaculture. Four survey methods were employed as part of a multi-species research programme to develop methods for surveying marine mammals and seabird populations in aquaculture management areas. Two of the techniques, involving continuous time- lapse photography of mussel farms and boat-based surveys through coastal farms were developed for this study. Time- lapse cameras showed that mussel farms buoys were used by king shags as temporary resting sites only. King shags were recorded on 36% of the farms (n = 44) from 13 surveys within inner Admiralty Bay. The low number of sightings within mussel farms suggests that farms are not important foraging or resting areas for king shags, at least in Admiralty Bay. The foraging range and density of king shags was not known before farms were developed, so no direct comparison or impact assessment can be made. Boat-based surveys were used to estimate the density of foraging shags, which showed that daily locations of foraging birds at sea can vary considerably on consecutive days and over the season. Previous environmental surveys to assess impacts of mussel farms on foraging areas are therefore unlikely to adequately represent the entire foraging range or most important feeding areas. The number of breeding pairs, chicks and nests was also found to vary considerably at colonies, dependent on when counts were undertaken during their protracted breeding season. Open water mid-bay aquaculture (shellfish and finfish) potentially poses a greater threat to king shags than ‘coastal ribbon development’, in terms of loss of open water habitat from farm structures, and loss of foraging habitat through modification to the water column (e.g., turbidity) and seabed. Given the lack of knowledge about the king shag population dynamics, diet and prey availability, there is an urgent requirement for more research to fill these gaps and also understand how we can conserve important shag feeding areas and associated marine environment through sustainable management of aquaculture.

A total of 730 variable oystercatchers (Haematopus unicolor) were recorded during a survey of the entire 1,500 km coastline of the Marlborough Sounds, New Zealand in spring 2006. This included 347 breeding pairs, 28 single birds and a non-breeding flock of 8 birds. The distribution of oystercatchers was influenced by habitat and human development, with fewer birds found in the inner sounds, where there is most development, and in the exposed outer coastline, where cliff or boulder habitat is limiting. Using similar methods of coastal surveys during the breeding season, the estimated national population of oystercatchers has increased from 2000 birds in 1970-71 to 7000 birds in 2006. This represents a population growth rate of 3.5% per annum. Winter flock counts give lower population estimates and coastal surveys are recommended for future monitoring of this species.

We estimated apparent annual survival of adult and young grey-faced petrels (Pterodroma macroptera gouldi) and age of first return to the natal colony of young birds from 2 colonies in the Bay of Plenty, New Zealand, between 1991 and 2008. We analysed the capture histories of 5844 adult birds and 928 chicks in a mark-recapture framework. The apparent adult annual survival rate was 0.89 after accounting for transience effects, which were greater at the mainland site (Mauao, Mount Maunganui) than on the island colony (Motuotau, Rabbit Island). Annual survival of young birds between fledging and 2 years of age was 0.844 for Mauao and 0.865 for Motuotau. Around 50% of fledglings that returned to their natal colony did so by 4 years of age, and by age 6, the probability of a fledgling returning was approximately 1.0. These are the first reliable estimates of these parameters for grey-faced petrels and are vital for models aimed at predicting the effects of natural perturbations or management interventions on breeding populations.